Belgium scored two late goals to force extra-time and then Youri Tielemans netted a penalty at the death as a stunned Senegal were beaten 3-2 in a roller-coaster World Cup last-32 clash on Wednesday.
Habib Diarra and Ismaila Sarr scored either side of the break as the West Africans seemed to be cruising to victory.
But substitute Romelu Lukaku's smart finish at the near post gave Belgium hope on 86 minutes and captain Tielemans headed in three minutes later.
An additional 30 minutes passed by with both sides going close before Lamine Camara's foul on Tielemans, and a long video review, allowed the skipper to convert a spot-kick deep into stoppage time at the end of extra-time.
"There are always situations where you can't quite believe it," Belgium coach Rudi Garcia said. "To finish it off with a correctly awarded penalty is great."
The Belgians - including a smattering of the "golden generation" who finished third in 2018 - will be back in Seattle on Monday to play either co-hosts the US or Bosnia and Herzegovina, who meet later on Wednesday.
Senegal began the year by beating Morocco on the pitch in the African Cup of Nations final, only to have victory taken away from them weeks later by officials, who punished them for leaving the field in a row with the referee.
Now Pape Thiaw's team have snatched defeat from the jaws of victory on the pitch as well after one of the wildest games at this World Cup.
Tielemans at the double
Leandro Trossard had an early chance for the Red Devils, but Sarr soon went closer at the other end when the Senegal forward bundled the ball against the frame of the goal.
He hit the post again via a header from Sadio Mané's cross, but this time the ball rebounded for Diarra to score on 24 minutes.
Garcia threw on Belgium record scorer Lukaku at half-time but instead it was the West Africans who came out all guns blazing.
Diarra spurned a big chance for his second but almost immediately, Sarr chested down a long ball superbly and blasted home on 51.
It was the fourth goal at this World Cup for the Crystal Palace forward.
Belgium barely reacted until Lukaku's 86th-minute strike. Their apparently impending exit was summed up by Trossard and Tielemans having to be separated by team-mates during an argument.
But the pair later combined for the leveller as Mory Diaw's ill-fated attempt at a punch permitted Tielemans to head home on 89th.
And the Aston Villa man had the last word at the very end of extra-time, winning and converting a penalty amid high drama in Seattle.
"I don’t want to comment on the referee’s decision," Senegal coach Thiaw said after Said Martinez spent a long time at the monitor.
"We’ve been knocked out and that hurts. We couldn’t hold on to that 2-0 lead. We must congratulate Belgium."
